1. Field of the Invention
The invention relates to Universal Serial Bus (USB) electrical connectors, and more particularly to low-profile USB connectors that can be stably and reliably mounted on a printed circuit board.
2. Description of the Prior Art
The trend toward miniaturization of electronic devices demands that many such devices have a low profile. Accordingly, electrical connectors in an electronic device should have a low profile above a printed circuit board on which the connectors are mounted. In order to achieve this, a lower portion of such connectors is mounted below the printed circuit board. Examples of such mounting are disclosed in U.S. Pat. No. 4,457,570 and Taiwan Pat. Application No. 87217216. FIG. 1 shows a Universal Serial Bus (USB) connector with locating means, as disclosed in the Taiwan Pat. Application No. 87217216. Two side wings extend from two side walls of a metal shell 901 of a USB connector 9. A through hole 91 is defined in each side wall. When the connector 9 is located in a cutout 95 of a circuit board 94, the through holes 91 are aligned with two holes 92 defined in the circuit board 94. The connector 9 can thereby be firmly latched to the circuit board 94 by using two bolts 93 extended through the through holes 91 and the holes 92.
Each side wing 90 must be large enough to accommodate a through hole 91, as well as provide sufficient area for soldering of the side wing 90 to the circuit board 94. This takes up valuable space on the circuit board 94 that could otherwise be used to accommodate more circuitry and components. Additionally, USB specifications require that two resilient tabs 902 be formed at each of upper and lower walls of the shell 901 of the USB connector 9, for engaging with a shell of a USB plug and attaining effective shielding and grounding. The side wings 90 are formed by stamping of the lower wall of the shell 901, and the tabs 902 are also formed by stamping of the very same lower wall. Therefore the amount of the lower wall available for stamping of the side wings 90 is limited.
Accordingly, an improved low-profile USB connector having small and easily-formed grounding tabs is desired.
An object of the present invention is to provide a low-profile electrical connector, particularly a low-profile USB connector, which can be securely mounted on a printed circuit board and which has a shielding shell and grounding tabs that are easily formed.
Another object of the present invention is to provide a low-profile electrical connector, particularly a low-profile USB connector, which has grounding tabs that occupy minimal space on a circuit board on which the connector is mounted.
To achieve the above object, an electrical connector in accordance with a preferred embodiment of the present invention comprises an insulative housing, a plurality of conductive contacts, and a metal shell. The housing includes a main body, and a tongue board extending forwardly from a front of the main body. The housing has a front side, a rear side, and a plurality of channels defined therein. The contacts are received in the channels. Each contact includes a mating portion for electrically engaging with a mating connector, a fixing portion fixed in the housing, and a tail portion protruding from the rear side of the housing. The shell shields the housing, and comprises first and second conductive shields. The first shield includes a pair of two-pronged fixing portions depending from opposite sides of the first shield respectively, and adapted to engage in a circuit board. The second shield includes two arms depending from a top of the second shield over outer faces of opposite sidewalls of the second shield respectively. Each arm forms a bent portion at a lower end thereof, for soldering to the circuit board. Each bent portion is located higher than a bottom of the shell. Each sidewall forms a pair of spring tongues adapted for electrically engaging with a metal shell of a mating connector. The fixing portions are disposed at a rear of the arms and higher than the bottom of the shell.
The electrical connector in accordance with the preferred embodiment of the present invention is attached to the circuit board at four points evenly distributed around a periphery of the connector. The connector thus maintains sturdy and durable mechanical and grounding connection with the circuit board, even when it is subjected to unwanted force during docking or disengaging of the mating connector.
Other objects, advantages and novel features of the present invention will be drawn from the following detailed description of preferred embodiments of the present invention with attached drawings, in which: